This application claims the priority of German patent document 198 32 873.7, filed Jul. 22, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an electric vehicle having one or more separate electric energy supply units.
Electrically driven vehicles are very suitable for short-distance transport, for example, in city traffic. A disadvantage of such vehicles relative to those having internal-combustion engines is their smaller range.
In order to increase the range of electric vehicles, German Patent Document DE 195 09 625 A1 describes an electric car with a single-axle trailer, which houses a separate energy supply unit, for example, having a fuel cell, a battery or a generator. Such an arrangement, however, has the following disadvantages:
high carried mass which limits the range of the electric vehicle;
limited maneuverability; and limited speed.
It is an object of the invention to provide an improved electric vehicle, having an increased range.
This and other objects and advantages are achieved by the vehicle energy supply arrangement according to the invention, in which at least one of the units which supply electric energy, particularly for driving the electric vehicle, is detachably arranged as a compact module on the vehicle roof. The energy supply unit arranged on the vehicle roof may particularly be a supplementary energy supply unit which exists in addition to the main supply unit situated in the interior of the vehicle. When required (if, for example, a long-distance drive is planned), the supplementary energy supply unit can be mounted on the vehicle, to permit an increased range of the electric vehicle. Because of the good accessibility of the energy supply unit on the vehicle roof, it can be mounted and removed rapidly, without high expenditures.
In addition to being used specifically for increasing the range, the energy supply unit arranged on the roof may also be the single energy supply unit of the electric vehicle.
If the energy supply is exhausted, the whole energy supply unit or only its components, such as a battery, may be exchanged. Moreover, in the case of constructions with liquid or gaseous fuels, they can be refueled at gas stations without having to exchange the energy supply unit itself.
With regard in particular to German Patent Document DE 195 09 625 A1 referred to above, the vehicle according to the invention has the following advantages:
the vehicle has no speed limitation;
the vehicle maneuverability is not limited;
there is improved parking space utilization for the vehicle;
it requires small additionally carried mass;
it results in increased crash safety;
no official permit is required;
no additional devices on the vehicle are required with respect to traffic safety according to Motor Vehicle Traffic Regulations;
there is cooling of individual components of the energy supply unit while utilizing the air stream; and
there are simple and space-saving storage possibilities of the energy supply unit removed from the vehicle.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.